Libclang does not find its include directory on Linux

[IngoMeyer441]

On Linux (tested it on Debian buster), libclang does only search for system headers in the default system locations but not in clang's own include directory /usr/lib/llvm-6.0/lib/clang/6.0.0/include (the version depends on the installed clang package). This directory for example contains stddef.h, so chromatica currently cannot highlight common types like size_t. A simple workaround for this issue is adding clang's include directory to the global chromatica flags:

let g:chromatica#global_args = ['-isystem/usr/lib/llvm-6.0/lib/clang/6.0.0/include']

On macos, I did not experience such problems. Maybe Apple's libclang got some patches to read all include directories.

In my opinion, that is actually a libclang issue but users of chromatica should know about this (maybe a hint in the README file?). YouCompleteMe, which is also libclang based, brings its own copy of clang headers to avoid this issue. They have a very long issue about libclang search path problems.

[pierremoreau]

Thank you for the tip: I was experiencing the same issue and pulling my hair off trying to figure out what was going on! 🙂

[Iskustvo]

@IngoHeimbach, thanks a lot for the tip!
After adding

let g:chromatica#global_args = ['-isystem/usr/lib/clang/8.0.0/include']

the syntax highlighting improved a lot. However, Chromatica still doesn't highlight some header names.
For example vector, system_error, cstring and unistd.h in this file are not highlighted.

Is this normal or do I need to do anything else?

I have tried adding every path from

echo | clang -std=c++17 -v -E -x c++ -

with -I in .chromatica but nothing changed.